Frictionless clock contact



1929- H. E. WARREN I 1,738,467

FRICTIONLESS CLOCK CONTACT 1 Filed Oct. 25. 1928 Inventor:

Henry E. War-Pew y Hi5 AbZoPney Pat'ehted Dec. 3, 1929 II/JL/NITED"STATES PATENT OFFICE HENRY E. WARREN, OF ASHLANI), MASSACHUSETTS,ASSIGNOB TO WARREN TELE- CHRON COMPANY, OF ASHLAND, MASSACHUSETTS, ACORPORATION OF MAINE rnIo'rIonLnss oLocx CONTACT Application filed0ctober 23, 1928. Serial No. 314,465.

My invention relates to an electric contact making and breaking devicesuitable for obtaining timed electric impulses from a clock withoutimposing any additional load on the clock mechanism such as might stopit or inv terfere with its time keeping function. In many clock systemsmaster clocks are employed to send out electric impulses at timedintervals. Analogous functions are perlight, this work is liable tointerfere with the correct running of the clock movement. Light switchcontacts are objectionable because of the small amount of current thatcan be handled without destructive burning.

The purpose of my invention is to provide anexceptionally heavy contactpressure in a clockoperated device without imposing any appreciable loadon the clock movement whereby accurately timed currentimpulses ofconsiderable magnitude may be produced.

In carrying my invention into effect in the preferred form I provide ametallic pointer driven directly by the clockwork and permit saidpointer to pass between spaced metallic rollers the adjacent surfaces ofwhich are driven in the same direction and at the same or approximatelythe same speed as the pointer in such manner that the pointer ismomentarily and periodically firmly clasped between the rollers toestablish a contact therethrough without interfering with the normalmovement of the pointer.

The features of my invention which are believed to be novel andpatentab'le will be pointed out in the claims appended hereto. For abetter understanding of my invention reference is made in the followingdescription to the accompanying drawing, Fig. 1 of which shows apreferred invention as applied to an electrically wound 'clock, 2represents the relation of the contacting surfaces of the apparatus ofFig. 1 when contact is made and Fig. 3 represents a modification of thecontact device.

In the drawing, Fig. 1, I have represented embodiment of the wind themain spring of the clock.

the essential features of my invention as applied to a clock or watchmovement the main spring of which is arranged to be wound by an electricmotor which also serves to rotate the contacting rollers. Many of thedetails of the clock mechanism itself are not shown since in generalthey willbe similar to those employed in any standard clock or watchmovement. The clock winding motor is represented at the right of thecase 10 which may be assumed to contain the usual type of springdrivenclock or watch mechanism and the contact device is represented atthe'left. In the commercial form it will be understoodthat all parts ofthe device would preferably be assembled in a more compact form and becontained in the same casing.

The clock spring winding mechanism will be first described. 11represents an electric motor. It may be of the direct or alternatingcurrent type and'should-run at a substantially constant speed. It willbe constantly con nected to a suitable source of supplyand will be inoperation continuously except when the power supply fails. Its shaft 12is connected through reduction gears 13, 14; and 15 to a gear wheel 16.Wheel 16 is, free to rotate on shaft 17 extending from the interior tothe exterior of casing 10. Shaft 17 is the main clock sp ring windingshaft and is arranged to be rotated by motor 11 to keep the main spring(not shown) wound up. Secured to shaft 17 is a collar 18 into which isfastened one end of a spiral spring 19. The other end of'this spring isstraightened out and extends into the path of movement of a roller 20 onthe gear wheel 16. As wheel 16 is driven in the direction indicated bythe arrow thereon roller 20 will move against the free endv of spring 19and if the main clock spring is not fully wound up torque will betransmitted through spring 19, collar 18.and shaft 17 to stantiallyfully wound the torque transmitted will be suflicient to permit roller20 to pass over the free end of the spring and no more winding will takeplace until the main' spring tension has been reduced to a point wherethe roller 20 will again rotate shaft 17 through the lVhen subcured onthe second hand shaft of the clock movement, and 22 the second handsecured to bushing 21 by a flexible connection. In this case the secondhand is apiece of thin spring wire one end of which is wound in a spiralabout 21 and secured thereto. As the second hand moves in a clockwisedirection its outer end asses between. the. peripheries of two metallicwheels or rollers 23 and 24 driven from motor 11 through shaft 12, andgears 24, 25, 26, 27, 28, 29. The wheels and 24 are arranged to bedriven so that theiradjacent peripheral surfaces move in thesamedirection and at the same or approximately the same speed as thatportion of the second hand 22 which passes between them. Wheels 23 and24 are not in contact with each other but are spaced apart a smalldistance corresponding to about the thickness of the pointer 22 suchthat when the pointer 22 moves between them the pointer will bridge thegap and the rollers will squeeze the pointer to a greater or lesserextent depending on the adjustment. This condition is represented inFig. 2 where the parts are numbered as in Fig. 1.

The desired spacing of rollers 23 and 24 may be accomplished byarranging their shafts 30 and 31 incadjustable frames 32 and 33 which inturn are secured to shafts 34 and 35 respectively. The last mentionedshafts are pivoted in a supporting frame 36 and are provided withadjusting arms 37 and 38. Arm 38 and the exact position of wheel 24 areadjusted by means of the adjusting screws 39 between which the outer endof arm 38 extends and wheel 23 is spaced away from wheel 24 by anadjusting screw 40 on which the outer end of arm 37 rests. The smallamount of adjustment necessary is not sufficient to interfere with thegear mesh between gears 28 and 29 or between gears 26 and 27. Therollers are suitably insulated from each other in the supportingstructure. Gears 28 and 29 may be made of some non-conducting materialand frame 32 is then suitably insulated from 36 such that frames 32 and33 are electrically insulated from each other in the device except atthe moment when the metallic pointer 22 passes between and is grasped bywheels 23. and 24. At this moment, once per minute in the arrangementdescribed, a positive electric contact capable of making and breakingconsiderable current without damage is made between wheels 23 and 24without imposing any load on the clock movement through the second hand.It will be evident that a heavy contact pressure is ossible withoutimposing any load on the-c ock.

If the motion of the second hand is pulsatiiig, as it is in many clockand watch movements, there will be an exceedingly slight alteration inthe normal actual motion at the outer end of the second hand. However,at the moment when the second hand is grasped between the roller wheels23 and 24 it must move at its average rate and can not pulsate. This istaken care of where necessary by the flexible connection between thesecond hand and its drivingshaft as previously described. The averageeifect of such pulsations on the clock movement will be zero and therate gf the clock movement is not influenced there- In some cases I mayomit the gear driving connection between the rollers 23 and 24' so thatone of them becomes an idler roller. By proper adjustment the idlerroller will then be driven from the other roller through the pointer asit comes between them without imposing any load on the clock. Where onlya small amount of current is to be handled I may even omit one rollerentirely and arrange the contacting device and circuit as represented inFig. 3 where 22 is the second hand pointer, 21' its shaft of conductingmaterial, and 23 a driven roller having a peripheral movement equal tothat of the end of the pointer 22 which momentarily makes point contactwith the roller in one position. The resilient connection between thepointer and its shaft permits good contacting pressure between the endof the pointer and roller 23.

In case of an interruption in the power supply to motor 11, the wheels23 and 24 will obviously stop rotating and under this condition, unlessthe wheels are separated to allow pointer 22 to pass freely betweenthem, this will stop the clock. Ordinarily the clock will run until itsspringis completely unwound so that occasional interruptions in thepower supply of short duration will not interfere with its operation. Totake care of such conditions I prefer to employ a novoltage releaserelay represented at 42. The armature 43 of this relay is secured to ashaft 44. On the opposite end of this shaft is an arm 45 extendingbeneath the adjusting lever 37. Relay 42 is connected to the samesource' as motor 11 so that when power is on and the motor is operatingthe relay is energized and attracts its armature 43. Under thiscondition, arm 45 does not interfere with the adjusted position of arm37 which then rests, due to gravity, against stop screw 40 to correctlyposition wheel 23. When the power fails, and motor 11 stops, armature43' will 11 will then start. Belay 42 will operate andnormal operationof the contact device will be resumed. I

v I have indicated a secondary clock circuit at 46 which is controlledby the clock contact device of my invention. Due'to the unusually largeamount of current that may be successfully controlled, an unusuallylarge number of secondary .impulse clocks such as indicated at 47 may beconnected to the system without danger of failure due to feeblecurrentimpulses. Moreover, a high grade accurate watch or clock movementmay be employed as a master clock without having the contactor interferewith its accuracy.

WVhile I have described the contact as being made every minute the ratemay obviously be made anything desired and the same master clock mayhave additional contact devices of the same character for producingimpulses at different rates.

In accordance with the provisions of the patent statutes I havedescribed the principle of operation of my invention together with theapparatus which I now consider to represent the best embodiment thereof;but I desire to have it understood that the apparatus shown anddescribed is only illustrative and that the invention may be carried outby other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. An electric contact device comprising a pail-of rollers having spacedapart adjacent peripheral surfaces of conducting material, a clockdriven pointermountedfor rotation about an axis such that its free endpasses between the adjacentcperipheral surfaces of said rollers, thespacing of said rollers being such as to grasp the pointer as it movesbetween them, and means for driving sa1d rollers so that the adjacentperipheralsurfaces move in the same direction and at approximately thesame speed as that of the contacting portion of the pointer, saidcontacting portion being made of conducting material whereby an electriccontact is established between said rollers when the pointermovesbetween them.

2. A contact device comprising. a pair of rollers having adjacent spacedapart surfaces of conducting material, a clock driven conducting memberarranged to be moved between and to bridge the space between the adacent surfaces of saidrollers and means for driving said rollers sothat'the peripheral portions which are bridged by the clock drivenconductor move in the same direc- 1,

tion and at approximately the same speed as that of the conductor. a

3. A contact making clock comprising aj clock movement, a conductordriven thereby,

a second conductor, said conductors being mounted for rotation on axessuch that 1n one rotative position of the clock driven conductor, saidconductors touch each other to establish an electric circuit betweenthem, and means for moving the second mentioned conductor at the samespeed and in the same direction as the clock .driv'en conductor at thecontacting surfaces thereof whereby an electric contact is establishedwithout imposing load on the clock movement.

4. A contact device comprising a conductor arm mounted for rotationabout an axis, a timing device for moving said conductor about saidaxis, a roller having a peripheral surface of conducting materialpositioned adjacent to a point 1n the path of movement of the outer endof said conductor arm whereby electrical contact is made between saidarm and the peripheral portion of said roller once for each completerotation of said arm, and an electric motor for driving said roller suchthat the peripheral surface 7 thereof, with which contact is made bysaid arm, moves in the same direction and at apapproximately the samespeed as the clock driven arm at the point of contact.

5. An intermittent contact device comprising' a clock driven pointerhavin an outer end portion of conducting materlal, a pair of rollershaving adjacent peripheral portions of conducting material so positionedand spaced that the pointer moves between and establishes an electriccircuit between the adjacent peripheral portions of said rollers, meansfor driving said rollers so that the contacting surfaces move atapproximately the same speed and in the same direction when the circuitis made, and means for adjusting the spacing between said rollers.

6. An intermittent contact device -com prising a clock driven'pointer ofconducting material, a roller having a peripheral surface of conductingmaterial normally positioned adjacent to a point in the path of movementof the outer end of said pointer whereby an electrical contact is madebetween them during each revolution of said pointer, an electricmotorfor driving said roller such that it moves at approximately thesame speed and in the same direction as the pointer at the points ofcontact, a source said inotor for moving the roller out of contactingposition with said pointer. 7. A contact device for clocks comprism aclock driven pointer having an outer'en portion of conducting material,a pair of heral' surfaces rollers' being v my hand this 19th day ofOctober, 1928.

rollers having adjacent peri of conductin material, sai normallypositioned and spaced such that the conducting portion of the pointerbridges the gap'b'etween saidrollers at one point 1n its movement, anelectric motor for driving said rollers such that the peripheralsurfaces which make contact with the pointer move at approximately thesame speed and in the same direction as the contacting part of thepointer when contact is made, a source of supplyfor said motor, andmeans responsive to a failure of said source for separating said rollersto vthe extent necessary to allow the ointer to pass between then;without makmg contact.

8. A contactmaking clock, comprising a clock movement, a ointer ofconducting material driven there y, a roller having a surface ofconducting material positioned adjacent to a point in the path ofmovement of the outer end of the pointer whereby an electric contact isestablished between them once during each revolution of the pointer,means for drlvmg said roller at a uniform rate such that at the point ofcontact between the pointer and roller the contacting surfaces move inthe same direction and at approximately the samejspeed,-and a resilientdriving connection between said ointer and clock movement to compensator pulsating clock movements.

9. A contact making clock comprising a spring driven clock movement, apointer having an outer end comprised of conducting material driven bysaid clock movement, a

conducting surface normally ositioned adjacent to a point in the path 0movement of the pointer such that an electric contact is i made betweenthe conducting portion of said pointer and said conducting surfaceduring each revolution of the pointer, an electric motor for winding thespring of the clock and for moving said conducting surface at a speedand in a direction such that no load is imposed upon the clock movementby reason of the contact made between such conducting surface andpointer, a source of supply for said motor, and means responsive to afailure of the source of supply for moving said conducting surface to aposition where it will not be touched by the pointer. x

10. A contact making. clock comprising a spring driven clock movement,apointer having a conducting portion driven by said clock movement,moving conducting surfaces adapted to grasp the conducting portion ofsaid pointer, and establish an electric circuit therethrough at adefinite point in its path of its pointer being grasped by such con-HENRY E. WARREN.

